The Prex project is an open source initiative to provide a portable real-time operating system for embedded systems. Prex is designed specifically for small memory footprint platforms. It is written mainly in C language based on traditional microkernel architecture.

The Prex kernel provides only fundamental features for task, thread, memory, ipc, exception, and synchronization. The other basic OS functions - process, file system, application loading, and networking, are provided by the user mode servers. In addition, Prex provides a POSIX emulation layer in order to utilize existing *NIX applications. This design allows the system to perform both of the native real-time task and the generic UNIX process simultaneously without degrading real-time performance. Furthermore, it helps platform designers to construct OS by choosing suitable server tasks for their target requisition.

This repository contains a branch "prex" for the official prex releases plus additional enhancements in "master" for changes that haven't been merged into the main prex tarball.